Method and system for adaptive transcoding and transrating in a video network

• US 20050091696A1
• Filed: 09/13/2004
• Published: 04/28/2005
• Est. Priority Date: 09/15/2003
• Status: Active Grant

• Current Assignee: DIRECTV, LLC (AT&T, Inc.)
• Original Assignee: Digital Networks North America, Inc. (DEI Holdings Incorporated)
• Inventors: Westerhoff, David, Wolfe, Andrew L.
• Granted Patent: US 7,555,006 B2
• Time in Patent Office: Days
• US Class Current: 725/116
• CPC Class Codes: H04N 21/234309 by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4 or from Quicktime to Realvideo conversion of standards in analog television systems H04N7/01
• CPC Class Codes: H04N 21/23805 Controlling the feeding rate to the network, e.g. by controlling the video pump
• CPC Class Codes: H04N 21/2401 Monitoring of the client buffer
• CPC Class Codes: H04N 21/2402 Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 21/43637 involving a wireless protocol, e.g. Bluetooth, RF or wireless LAN [IEEE 802.11] arrangements for wireless networking or broadcasting of information in indoor or near-field type systems H04B10/114
• CPC Class Codes: H04N 21/440218 by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4 conversion of standards in analogue television systems H04N7/01
• CPC Class Codes: H04N 21/6131 involving transmission via a mobile phone network wireless downlink channel access H04W74/006

Abstract

A video server adaptively selects an appropriate video encoding standard and an appropriate video encoding rate for encoding video content to be downloaded to one or more video client devices over a communication network. The video server adaptively selects the video encoding standard and the video encoding rate based upon factors such as the data transmission rate of the communication network, the processing speed of the video client device, or the type of the video content to be downloaded. Once the video encoding standard and the video encoding rate are selected, video content can be transcoded prior to downloading to one or more video client devices. During the download, the video content may be adaptively transrated, such as in response to a change in the data transmission rate of the communication network.

Claims

1. An apparatus for downloading video content to a client device over a communication network, the apparatus comprising:

an encoder for encoding video content according to an initial video encoding standard and an initial video encoding rate;

a storage unit coupled to the encoder for storing the encoded video content;

a transcoder coupled to the storage unit for transcoding the video content stored in the storage unit according to a modified video encoding standard and a modified video encoding rate;

a communications interface coupled to the transcoder for downloading the video content to the client device over the communication network; and

a controller coupled to and controlling the storage unit, the encoder, the transcoder, and the communications interface, the controller monitoring and determining a transmission rate of the communication network and adaptively selecting the modified video encoding standard and the modified video encoding rate based on the determined transmission rate.

2. The apparatus of claim 1, wherein the transcoder converts the video content from the initial video encoding standard directly to the modified video encoding standard without decoding the video content.

3. The apparatus of claim 1, wherein the transcoder decodes the video content from the initial video encoding standard and re-encodes the video content to the modified video encoding standard.

4. The apparatus of claim 1, further comprising a transrater for altering the modified transmission rate of the video content, based on a change in the transmission rate of the communication network, during a download of the video content to the client device.

5. The apparatus of claim 1, wherein the modified video encoding standard is MPEG-1, MPEG-2 or MPEG-4.

6. The apparatus of claim 1, wherein the communication network is a wireless communication network.

7. An apparatus for downloading video content to a plurality of client devices over a communication network having a bandwidth, the apparatus comprising:

an encoder for encoding video content according to an initial video encoding standard and an initial video encoding rate;

a storage unit coupled to the encoder for storing the encoded video content;

a transcoder coupled to the storage unit for transcoding the video content stored in the storage unit according to a modified video encoding standard and a modified video encoding rate;

a communications interface coupled to the transcoder for downloading the video content to the client devices over the communication network; and

a controller coupled to and controlling the storage unit, the encoder, the transcoder, and the communications interface, the controller monitoring and determining the bandwidth of the communication network and allocating at least part of the bandwidth to each of the client devices, the controller adaptively selecting the modified video encoding standard and the modified video encoding rate based on the allocated bandwidth for each client device.

8. The apparatus of claim 7, wherein the transcoder converts the video content from the initial video encoding standard directly to the modified video encoding standard without decoding the video content.

9. The apparatus of claim 7, wherein the transcoder decodes the video content from the initial video encoding standard and re-encodes the video content to the modified video encoding standard.

10. The apparatus of claim 7, further comprising a transrater for transrating the video content to a different transmission rate than the modified transmission rate, based on a change on the transmission rate of the communication network, during a download of the video content to one of the client devices.

11. An apparatus for downloading video content to a client device over a communication network, the apparatus comprising:

an encoder for encoding video content according to an initial video encoding standard and an initial video encoding rate;

a storage unit coupled to the encoder for storing the encoded video content;

a transcoder coupled to the storage unit for transcoding the video content stored in the storage unit according to a modified video encoding standard and a modified video encoding rate;

a communications interface coupled to the transcoder for downloading the video content to the client device over the communication network; and

a controller coupled to and controlling the storage unit, the encoder, the transcoder, and the communications interface, the controller monitoring and determining the processing speed of the client device and adaptively selecting the modified video encoding standard and the modified video encoding rate based on the processing speed.

12. The apparatus of claim 11, wherein the transcoder converts the video content from the initial video encoding standard directly to the modified video encoding standard without decoding the video content.

13. The apparatus of claim 11, wherein the transcoder decodes the video content from the initial video encoding standard and re-encodes the video content to the modified video encoding standard.

14. The apparatus of claim 11, further comprising a transrater for transrating the video content to a different transmission rate than the modified transmission rate, based on a change in a transmission rate of the communication network, during a download of the video content to the client device.

15. The apparatus of claim 11, wherein the modified video encoding standard is MPEG-1, MPEG-2 or MPEG-4.

16. An apparatus for downloading video content to a client device over a communication network, the apparatus comprising:

an encoder for encoding video content according to an initial video encoding standard and an initial video encoding rate;

a storage unit coupled to the encoder for storing the encoded video content;

a transcoder coupled to the storage unit for transcoding the video content stored in the storage unit according to a modified video encoding standard and a modified video encoding rate;

a communications interface coupled to the transcoder for downloading the video content to the client device over the communication network; and

a controller coupled to and controlling the storage unit, the encoder, the transcoder, and the communications interface, the controller monitoring and determining the type of the video content to be downloaded and adaptively selecting the modified video encoding standard and the modified video encoding rate based on the type of the video content.

17. The apparatus of claim 16, wherein the transcoder converts the video content from the initial video encoding standard directly to the modified video encoding standard without decoding the video content.

18. The apparatus of claim 16, wherein the transcoder decodes the video content from the initial video encoding standard and re-encodes the video content to the modified video encoding standard.

19. The apparatus of claim 16, further comprising a transrater for transrating the video content to a different transmission rate than the modified transmission rate, based on a change in a transmission rate of the communication network, during a download of the video content to the client device.

20. The apparatus of claim 16, wherein the modified video encoding standard is MPEG-1, MPEG-2 or MPEG-4.

21. In a video server downloading video content to a video client device over a communication network, a method of downloading the video content from the video server to the video client device, the method comprising:

determining a transmission rate of the communication network;

adaptively selecting a video encoding standard and a video encoding rate based on the determined transmission rate of the communication network;

transcoding the video content from an initial video encoding standard and an initial video encoding rate to the selected video encoding standard and the selected video encoding rate; and

downloading the transcoded video content to the video client device over the communication network.

22. The method of claim 21, further comprising:

during the download of the transcoded video content to the video client device, detecting a change in the determined transmission rate of the communication network;

transrating a remaining portion of the video content that has not already been downloaded to the video client device; and

downloading the transrated remaining portion of the video content to the video client device.

23. The method of claim 21, wherein transcoding the video content comprises converting the video content from the initial video encoding standard and the initial video encoding rate directly to the selected video encoding standard and the selected video encoding rate without decoding the video content.

24. The method of claim 21, wherein the selected video encoding standard is MPEG-1, MPEG-2 or MPEG-4.

25. In a video server downloading video content to a plurality of video client devices over a communication network having a bandwidth, a method of downloading the video content from the video server to the video client devices, the method comprising:

determining an available bandwidth of the communication network;

allocating at least part of the available bandwidth to a first video client device and a second video client device;

adaptively selecting respective video encoding standards and video encoding rates for the first and second video client devices based on the available bandwidth allocated to the first and second client devices;

transcoding the video content from an initial video encoding standard and an initial video encoding rate to the respective selected video encoding standards and selected video encoding rates; and

downloading the transcoded video content to first and second client devices over the communication network

26. The method of claim 25, further comprising:

during the download of the transcoded video content to the first video client device, detecting a change in the available bandwidth of the communication network;

based on the change in the available bandwidth, transrating a remaining portion of the video content that has not already been downloaded to the first video client device; and

downloading the transrated remaining portion of the video content to the first video client device.

27. The method of claim 25, further comprising:

during the download of the transcoded video content to the first video client device, detecting a change in the available bandwidth of the communication network;

reallocating at least part of the available bandwidth among the first and second video client devices;

based on the reallocated available bandwidth, transrating respective portions of the video content that have not already been downloaded to the first and second video client devices; and

downloading the respective transrated portions of the video content to the first and second video client devices.

28. The apparatus of claim 25, wherein transcoding the video content comprises converting the video content from the initial video encoding standard and the initial video encoding rate directly to the selected video encoding standards and video encoding rates without decoding the video content.

29. The method of claim 25, wherein at least one of the selected video encoding standards is MPEG-1, MPEG-2 or MPEG-4.

30. In a video server downloading video content to a video client device over a communication network, a method of downloading the video content from the video server to the video client device, the method comprising:

determining a processing capability of the video client device;

selecting a video encoding standard and a video encoding rate based on the determined processing capability;

transcoding the video content from an initial video encoding standard and an initial video encoding rate to the selected video encoding standard and the selected video encoding rate; and

downloading the transcoded video content to the video client device over the communication network.

31. The method of claim 30, further comprising:

determining a current data transmission rate of the communication network; and

wherein selecting the video encoding standard and the video encoding rate comprises selecting the video encoding standard and the video encoding rate based on the determined processing capability and the current data transmission rate of the communication network.

32. The method of claim 31, further comprising:

during the download of the video content to the video client device, detecting a change in the current data transmission rate of the communication network;

transrating a remaining portion of the video content that has not already been downloaded to the video client device; and

downloading the transrated remaining portion of the video content to the client device.

33. The apparatus of claim 30, wherein transcoding the video content comprises converting the video content from the initial video encoding standard and the initial video encoding rate directly to the selected video encoding standard and the selected video encoding rate without decoding the video content.

34. The method of claim 30, wherein the selected video encoding standard is MPEG-1, MPEG-2 or MPEG-4.

35. In a video server downloading video content to a video client device over a communication network, a method of downloading the video content from the video server to the video client device, the method comprising:

determining the type of the video content to be downloaded;

selecting a video encoding standard and a video encoding rate based on the determined type of the video content;

transcoding the video content form an initial video encoding standard and an initial video encoding rate to the selected video encoding standard and the selected video encoding rate; and

downloading the transcoded video content to the video client device over the communication network.

36. The method of claim 35, further comprising:

determining a current data transmission rate of the communication network; and

wherein selecting the video encoding standard and the video encoding rate comprises selecting the video encoding standard and the video encoding rate based on the determined type of the video content and the current data transmission rate of the communication network.

37. The method of claim 36, further comprising:

during the download of the video content to the video client device, detecting a change in the current data transmission rate of the communication network;

transrating a remaining portion of the video content that has not already been downloaded to the video client device; and

downloading the transrated remaining portion of the video content to the client device.

38. The apparatus of claim 35, wherein transcoding the video content comprises converting the video content from the initial video encoding standard and the initial video encoding rate directly to the selected video encoding standard and the selected video encoding rate without decoding the video content.

39. The method of claim 35, wherein the selected video encoding standard is MPEG-1, MPEG-2 or MPEG-4.